A. Field of the Invention
The present invention relates to the prevention and treatment of cancer through the use of chemopreventative agents.
B. Background of the Invention
Prostate cancer is the most common malignant transformation that occurs in men and its incidence is increasing at an alarming rate. Prostate cancer ranks as the most serious task facing both doctors and their male patients. Unfortunately, the major cause of death from prostate cancer comes in the hormone-refractory metastatic stage of the disease for which no treatment options are available at present.
Complicating the diagnosis and treatment of prostate cancer is the fact that prostate cancer remains latent and harmless in most individuals; clinically evident in many individuals, and virulent in still others. These variations in the expression of prostate concern make it even more difficult to derive efficacious treatment regimens. The therapies that are now available are associated with side effects which include impotence in about 59.9% men after 18-months of prostatectomy.
Over the past several years chemoprevention has been established as a meaningful approach to control malignancy. Chemopreventative approaches use either natural and/or synthetic compounds to intervene in the early pre-cancerous stages of carcinogenesis before cancer actually begins and thus having a greater chance of total cure. Like most cancers, prostate cancer is a complex process involving alterations in the balance between cell proliferation and cell death and accumulation of a series of genetic changes. Such an alteration exists in prostate cancer and in benign prostate hyperplasia (BPH). In BPH, the apoptotic index (percentage of cells undergoing apoptosis) is significantly reduced in the epithelial cells, basal cells and the stromal cells, while at the same time the proliferative index is significantly increased in all three cell types. These changes occur over a long period of time thus providing a large window of opportunity to i) prevent its induction; ii) inhibit the development of pre-invasive or invasive neoplasia and iii) its progression by using chemopreventative agents.
It is well known that prostate cancer is highly heterogeneous in that the tumor contains a population of both androgen-dependent and independent cells and also cells at different stages of transition between androgen-dependence and independence. Androgen ablation is, to date, the therapy of choice and is widely used to inhibit prostate cancer in the initial stages of prostate concern; however, the likelihood of recurrence of tumors (androgen-independent) limits this therapeutic approach. The average survival time after failing androgen-ablation therapy is about 12 months.
Prostate specific antigen (PSA) has traditionally been used as a tumor marker to detect prostate cancer. Many studies have demonstrated that most of the patients with established benign prostatic hyperplasia (BPH) undergoing prostatectomy have abnormal levels of PSA. 10 years after surgery approximately 25% of patients with PSA levels between 4-10 ng/ml; 70% between 10-20 ng/ml and 72% for men with PSA levels greater than 20 ng/ml develop prostate cancer. In addition, men with PSA levels of 2-4 have a 30% chance of developing prostate cancer after 5 years.
In view of the above, there is a dire need for more effective preventative and therapeutic approaches in dealing with prostate cancer specifically and, of course, all cancers for which there is no presently available and reliable cure.
It is, therefore, an object of the present invention to provide a new modality for the prevention of cancer.
It is another object of the present invention to provide a new modality for the treatment of cancer.
It is another object of the present invention to provide a new modality for the treatment of prostate cancer.
It is another object of the present invention to provide a method by which the known substance of eugenol may be employed in a new and unobvious manner in the prevention and/or treatment of cancers, including prostate cancer.
It is another object of the present invention to provide a method by which the known substance of eugenol may, in combination with synergistic compounds, including 2-ME, be employed in the prevention and/or treatment of cancers, including prostate cancer.
In satisfaction of these and related objects, disclosed and claimed herein is the use of eugenol, alone and in combination with 2-methoxyestradiol (2-ME) in the context of prostate cancer prophylaxes and treatment.
Eugenol is a major component of the essential oils from bay leaves and the buds of cloves (Eugenia Caryophyllata). It is widely used as a flavoring agent in food products, pharmaceuticals products and also as an analgesic in dentistry. However, nothing has been heretofore known about eugenol""s capacity for preventing and treating cancer.
The use of eugenol either alone or in combination with 2-ME offers the following important advantages: i) since eugenol has been used as an analgesic successfully in the dentistry, toxicity is unlikely; (ii) cell cycle analysis data indicated that eugenol inhibited the growth of suspect cells without any significant alterations in the cells cycle profile, thereby indicating a different mechanism of action than that of 2-ME when used in the same context; (iii) yet, eugenol demonstrated synergistic activity with 2-ME. The present inventors have shown that 2-ME inhibits the growth of cells by inducing apoptosis and blocking cells in G2/M phase. Therefore induction of cell death pathway by 2-ME and growth inhibition by eugenol through a different pathway presents a tremendous new weapon for use in preventing and combating cancer.